Adding additional information to cart/order/packing slip

[Talib]

Hi

I posted this already but I think in the wrong part of the forum, so I am reposting it here:

Been reading through this forum and can't find any help. I have the situation where two different products can have the same name, yet are in different categories.

Now my dillema is that on the shopping cart and order and packing slip only the name appears and not the category which it came from (or at least the product id). So far it looks like I need to edit templates. I think I found the files I am suppose to edit:

admin/invoice.php
admin/packingslip.php
includes/templates/MYTEMPLATE/templates/tpl_shopping_cart_default.php (using override)

I tried this in invoice.php:

<td class="dataTableContent" valign="top">' . $order->products[$i]['name'] . $order->products[$i]['id'];

yet to no avail, then I tried this:

<td class="dataTableContent" valign="top">' . $order->products[$i]['name'] . $order->products[$i]['name'];

which resulted in the name being printed twice at the right place, so I am on the right track. Why is 'id' not working?

PS Changing the cart is not critical, however, the invoice and packing slip is. There is no need to display the model on the packing slip or invoice so that can be replaced with category (I am using model for other details and thus can't use it to display the category it is in)